U.S. patent number 10,113,747 [Application Number 14/687,866] was granted by the patent office on 2018-10-30 for systems and methods for control of combustion dynamics in combustion system.
This patent grant is currently assigned to General Electric Company. The grantee listed for this patent is General Electric Company. Invention is credited to Sarah Lori Crothers, Joel Meador Hall, Hasan Karim.
United States Patent |
10,113,747 |
Crothers , et al. |
October 30, 2018 |
Systems and methods for control of combustion dynamics in
combustion system
Abstract
The present disclosure generally relates to a system with a gas
turbine engine. The gas turbine engine includes a first combustor
having a first fuel injector and a second combustor having a second
fuel injector. The gas turbine engine further includes a first fuel
conduit extending from a first orifice to a first fuel outlet of
the first fuel injector. The first fuel conduit has a first
acoustic volume between the first orifice and the first fuel
outlet. The gas turbine engine further includes a second fuel
conduit extending from a second orifice to a second fuel outlet of
the second fuel injector. The second fuel conduit has a second
acoustic volume between the second orifice and the second fuel
outlet, and the first acoustic volume and the second acoustic
volume are different from one another.
Inventors: |
Crothers; Sarah Lori
(Greenville, SC), Karim; Hasan (Simpsonville, SC), Hall;
Joel Meador (Greenville, SC) |
Applicant: |
Name |
City |
State |
Country |
Type |
General Electric Company |
Schenectady |
NY |
US |
|
|
Assignee: |
General Electric Company
(Schenectady, NY)
|
Family
ID: |
57043852 |
Appl.
No.: |
14/687,866 |
Filed: |
April 15, 2015 |
Prior Publication Data
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|
|
Document
Identifier |
Publication Date |
|
US 20160305337 A1 |
Oct 20, 2016 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F23N
5/247 (20130101); F23R 3/34 (20130101); F23R
3/44 (20130101); F05D 2260/964 (20130101); F23R
2900/00014 (20130101); F05D 2240/35 (20130101) |
Current International
Class: |
F23R
3/34 (20060101); F23N 5/24 (20060101); F23R
3/44 (20060101) |
References Cited
[Referenced By]
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1632718 |
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Mar 2006 |
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EP |
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2031192 |
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Mar 2009 |
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EP |
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881935 |
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Nov 1961 |
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GB |
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2009281720 |
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Dec 2009 |
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JP |
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2012102733 |
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May 2012 |
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JP |
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Other References
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applicant.
|
Primary Examiner: Kim; Craig
Assistant Examiner: Kang; Edwin
Attorney, Agent or Firm: Wilson; Charlotte C. Cusick; Ernest
G. Landgraff; Frank A.
Claims
The invention claimed is:
1. A system, comprising: a gas turbine engine, comprising; a first
combustor comprising a first liner circumscribing a first primary
combustion zone and a first secondary combustion zone downstream of
the first primary combustion zone and a first fuel injector
disposed along the first liner and configured to inject a fuel, via
a first fuel outlet, through the first liner into the first
secondary combustion zone of the first combustor, the first fuel
injector being located at a first distance from a first outlet of
the first combustor; a second combustor comprising a second liner
circumscribing a second primary combustion zone and a second
secondary combustion zone downstream of the second primary
combustion zone and a second fuel injector disposed along the
second liner and configured to inject the fuel, via a second fuel
outlet, through the second liner into the second secondary
combustion zone of the second combustor, the second fuel injector
being located at a second distance from a second outlet of the
second combustor; a first fuel conduit extending axially along a
first outer surface of the first liner and supplying the fuel to
the first fuel injector; a first pre-orifice installed inside the
first fuel conduit, such that a first volume of the first fuel
conduit is defined between the first pre-orifice and the first fuel
outlet; a second fuel conduit extending axially along a second
outer surface of the second liner and supplying the fuel to the
second fuel injector; and a second pre-orifice installed inside the
second fuel conduit, such that to a second volume of the second
fuel conduit is defined between the second pre-orifice and the
second fuel outlet, wherein the first volume and the second volume
are different from one another; and wherein the first distance is
equal to the second distance; wherein the first pre-orifice
comprises a first geometry, and the second pre-orifice comprises a
second geometry, wherein one or more first geometric differences
between the first geometry of the first pre-orifice and the second
geometry of the second pre-orifice reduce coherence between the
first combustor and the second combustor or alter a phase between
the first combustor and the second combustor; and wherein the one
or more first geometric differences between the first geometry of
the first pre-orifice and the second geometry of the second
pre-orifice comprises one or more of a number of orifices and an
arrangement of a plurality of orifices.
2. The system of claim 1, wherein the first combustor comprises a
first fuel nozzle upstream from the first fuel injector, the first
fuel nozzle being configured to inject the fuel into the first
primary combustion zone of the first combustor; and wherein the
second combustor comprises a second fuel nozzle upstream from the
second fuel injector, the second fuel nozzle being configured to
inject the fuel into the second primary combustion zone of the
second combustor.
3. The system of claim 1, wherein the one or more first geometric
differences between the first geometry of the first pre-orifice and
the second geometry of the second pre-orifice additionally
comprises one or more of an orifice shape, an orifice dimension, an
axial position, and a cross-sectional area.
4. The system of claim 1, wherein the first fuel conduit comprises
a first conduit geometry and the second fuel conduit comprises a
second conduit geometry, and wherein one or more second geometric
differences between the first conduit geometry and the second
conduit geometry alter a phase and/or reduce coherence between the
first combustor and the second combustor.
5. The system of claim 4, wherein the one or more second geometric
differences between the first conduit geometry and the second
conduit geometry comprises one or more of a length, a width, a
diameter, an inner surface, and a shape.
6. A system, comprising: a first combustor of a gas turbine system,
comprising: a first liner circumscribing a first primary combustion
zone and a first secondary combustion zone downstream of the first
primary combustion zone; a first fuel injector disposed along the
first liner and comprising a first fuel outlet configured to inject
a fuel through the first liner into the first secondary combustion
zone, the first fuel injector being located at a first distance
from a first outlet of the first combustor; a second fuel injector
disposed along the first liner and comprising a second fuel outlet
configured to inject the fuel through the first liner into the
first secondary combustion zone, the second fuel injector being
located at a second distance from the first outlet of the first
combustor; a first fuel conduit extending axially along an outer
surface of the first liner and supplying the fuel to the first fuel
injector; a first pre-orifice installed inside the first fuel
conduit, wherein the first fuel conduit has a first conduit
geometry between the first pre-orifice and the first fuel outlet,
and wherein the first pre-orifice has a first pre-orifice geometry;
a second fuel conduit extending axially along the first outer
surface of the first liner and supplying the fuel to the second
fuel injector; and a second pre-orifice installed inside the second
fuel conduit, wherein the second fuel conduit has a second conduit
geometry between the second pre-orifice and the second fuel outlet,
and wherein the second pre-orifice has a second pre-orifice
geometry; wherein the first conduit geometry and the second conduit
geometry are different from one another, or the first pre-orifice
geometry and the second pre-orifice geometry are different from one
another, or a combination thereof; and wherein the first distance
is equal to the second distance; and wherein one or more first
geometric differences between the first pre-orifice geometry of the
first pre-orifice and the second pre-orifice geometry of the second
pre-orifice comprise differences in a number of orifices or an
arrangement of a plurality of orifices.
7. The system of claim 6, wherein the one or more first geometric
differences between the first pre-orifice geometry of the first
pre-orifice and the second pre-orifice geometry of the second
pre-orifice additionally comprise differences in an orifice shape,
an orifice dimension, an axial position, or a cross-sectional
area.
8. The system of claim 6, wherein the first fuel outlet comprises a
third orifice geometry and the second fuel outlet comprises a
fourth orifice geometry, wherein the third orifice geometry is
different from the fourth orifice geometry.
9. The system of claim 6, wherein the first conduit geometry
between the first pre-orifice and the first fuel outlet corresponds
to a first volume between the first pre-orifice and the first fuel
outlet; wherein the second conduit geometry between the second
pre-orifice and the second fuel outlet corresponds to a second
volume between the second pre-orifice and the second fuel outlet;
and wherein the second volume is different from the first
volume.
10. The system of claim 9, wherein one or more differences between
the first volume and the second volume reduce combustion dynamics
amplitudes between the first fuel injector and the second fuel
injector of the first combustor.
11. The system of claim 6, wherein the system comprises a second
combustor comprising a second liner circumscribing a second primary
combustion zone and a second secondary combustion zone; and wherein
the second combustor is equipped with a third fuel injector in
fluid communication with a third fuel conduit, the third fuel
injector being disposed along the second liner and configured to
inject the fuel through the second liner into the second secondary
combustion zone, the third fuel injector being located at a third
distance from a second outlet of the second combustor; and wherein
the third fuel conduit extends axially along a second outer surface
of the second liner and has one or more second geometric
differences relative to the first fuel conduit or the second fuel
conduit of the first combustor, and the third distance is equal to
the first distance.
12. A gas turbine engine comprising: a first combustor comprising;
a first liner circumscribing a first primary combustion zone and a
first secondary combustion zone downstream of the first primary
combustion zone; a first fuel injector disposed along the first
liner and configured to inject a fuel, via a first fuel outlet,
through the first liner into the first secondary combustion zone of
the first combustor, the first fuel injector being located at a
first distance from a first outlet of the first combustor; a first
fuel conduit extending axially along a first outer surface of the
first liner and supplying the fuel to the first fuel injector, the
first fuel conduit having a first cross-sectional diameter; and a
first pre-orifice installed inside the first fuel conduit, such
that a first volume of the first fuel conduit is defined between
the first pre-orifice and the first fuel outlet; a second combustor
comprising: a second liner circumscribing a second primary
combustion zone and a second secondary combustion zone downstream
of the second primary combustion zone; a second fuel injector
disposed along the second liner and configured to inject the fuel,
via a second fuel outlet, through the second liner into the second
secondary combustion zone of the second combustor, the second fuel
injector being located at a second distance from a second outlet of
the second combustor, wherein the second distance is equal to the
first distance; a second fuel conduit extending axially along a
second outer surface of the second liner and supplying the fuel to
the second fuel injector, the second fuel conduit having a second
cross-sectional diameter different from the first cross-sectional
diameter; a second pre-orifice installed inside the second fuel
conduit, such that a second volume of the second fuel conduit is
defined between the second pre-orifice and the second fuel outlet;
wherein the first volume is different from the second volume; and
wherein the first pre-orifice has at least one first geometric
difference from the second pre-orifice, the at least one first
geometric difference being a difference in a number of orifices and
a difference in a arrangement of a plurality of orifices.
13. The gas turbine engine of claim 12, wherein the first fuel
conduit and the second fuel conduit have at least one second
geometric difference in addition to a difference between the first
cross-sectional diameter and the second cross-sectional diameter,
the at least one second geometric difference comprising a
difference in length, a difference in an inner surface, and a
difference in conduit shape.
14. The gas turbine engine of claim 12, wherein the at least one
first geometric difference additionally comprises a difference in
an orifice shape, a difference in an orifice dimension, a
difference in a cross-sectional area, and a difference in an axial
position of a respective pre-orifice within a respective fuel
conduit.
Description
BACKGROUND
The subject matter disclosed herein relates generally to gas
turbine systems, and more particularly, to systems and methods for
reducing combustion dynamics, and more specifically, for reducing
modal coupling of combustion dynamics within a gas turbine
engine.
Gas turbine systems generally include a gas turbine engine having a
compressor section, a combustor section, and a turbine section. The
combustor section may include one or more combustors (e.g.,
combustion cans), each combustor having a primary combustion system
and a secondary combustion system (e.g., late lean injection (LLI)
system) downstream from the primary combustion system. A fuel
and/or air mixture may be routed into the primary and secondary
combustion systems through fuel nozzles, and each combustion system
may be configured to combust the mixture of the fuel and air to
generate hot combustion gases that drive one or more turbine stages
in the turbine section.
The generation of the hot combustion gases can create a variety of
combustion dynamics, which occur when the combustor acoustic
oscillations interact with the flame dynamics (also known as the
oscillating component of the heat release), to result in a
self-sustaining pressure oscillation in the combustor. Combustion
dynamics can occur at multiple discrete frequencies or across a
range of frequencies, and can travel both upstream and downstream
relative to the respective combustor. For example, the pressure
waves may travel downstream into the turbine section, e.g., through
one or more turbine stages, or upstream into the fuel system.
Certain components of the turbine system can potentially respond to
the combustion dynamics, particularly if the combustion dynamics
generated by the individual combustors exhibit an in-phase and
coherent relationship with each other, and have frequencies at or
near the natural or resonant frequencies of the components. In the
context of combustion dynamics, "coherence" refers to the strength
of the linear relationship between two dynamic signals, and is
strongly influenced by the degree of frequency overlap between
them. In the context of combustion dynamics, "coherence" is a
measure of the modal coupling, or combustor-to-combustor acoustic
interaction, exhibited by the combustion system.
Accordingly, a need exists to control the combustion dynamics,
and/or modal coupling of the combustion dynamics, to reduce the
possibility of any unwanted sympathetic vibratory response (e.g.,
resonant behavior) of components in the turbine system.
BRIEF DESCRIPTION
Certain embodiments commensurate in scope with the originally
claimed invention are summarized below. These embodiments are not
intended to limit the scope of the claimed invention, but rather
these embodiments are intended only to provide a brief summary of
possible forms of the invention. Indeed, the invention may
encompass a variety of forms that may be similar to or different
from the embodiments set forth below.
In a first embodiment, a system includes a gas turbine engine. The
gas turbine engine includes a first combustor having a first fuel
injector and a second combustor having a second fuel injector. The
gas turbine engine further includes a first fuel conduit extending
from a first orifice to a first fuel outlet of the first fuel
injector. The first fuel conduit has a first acoustic volume
between the first orifice and the first fuel outlet. The gas
turbine engine further includes a second fuel conduit extending
from a second orifice to a second fuel outlet of the second fuel
injector. The second fuel conduit has a second acoustic volume
between the second orifice and the second fuel outlet, and the
first acoustic volume and the second acoustic volume are different
from one another.
In a second embodiment, a system includes a first combustor of a
gas turbine system. The first combustor includes a first fuel
injector having a first fuel outlet and a second fuel injector
having a second fuel outlet. The first combustor further includes
the first fuel conduit extending from a first orifice to the first
fuel outlet of the first fuel injector. The first fuel conduit has
a first conduit geometry between the first orifice and the first
fuel outlet and the first orifice has a first orifice geometry. The
first combustor further includes a second fuel conduit extending
from a second orifice to the second fuel outlet of the second fuel
injector. The second fuel conduit has a second conduit geometry
between the second orifice and the second fuel outlet and the
second orifice has a second orifice geometry. The first conduit
geometry and the second conduit geometry are different from one
another, or the first orifice geometry and the second orifice
geometry are different from one another, or a combination
thereof.
In a third embodiment, a system includes a first fuel conduit
extending from a first orifice to a first fuel outlet of a first
fuel injector of a gas turbine engine. The first fuel conduit has a
first conduit geometry between the first orifice and the first fuel
outlet, and the first orifice has a first orifice geometry. The
system further includes a second fuel conduit extending from a
second orifice to a second fuel outlet of a second fuel injector of
the gas turbine engine. The second fuel conduit has a second
conduit geometry between the second orifice and the second fuel
outlet. The second orifice has a second orifice geometry different
from the first orifice geometry, or the second conduit geometry is
different from the first conduit geometry.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other features, aspects, and advantages of the present
invention will become better understood when the following detailed
description is read with reference to the accompanying drawings in
which like characters represent like parts throughout the drawings,
wherein:
FIG. 1 is a schematic of an embodiment of a gas turbine system
having a plurality of combustors, where each combustor is equipped
with a late lean injection (LLI) fuel circuit;
FIG. 2 is a schematic of an embodiment of one of the combustors of
FIG. 1, including one or more fuel lines within the LLI fuel
circuit, where the position of a pre-orifice within each fuel line
varies from one fuel line to another to help control combustion
dynamics and/or modal coupling of combustion dynamics to reduce the
possibility of unwanted vibratory responses in downstream
components;
FIG. 3 is a cross-sectional schematic of an embodiment of a
cross-sectional view of the combustor of FIG. 2, taken along line
3-3, illustrating the one or more fuel lines configured to route a
secondary fuel from the pre-orifice to a post-orifice;
FIG. 4 is a schematic of an embodiment of the gas turbine system of
FIG. 1, illustrating a plurality of combustors each having one or
more fuel supply systems;
FIG. 5 is a schematic of an embodiment of two fuel supply systems
coupled to a combustor of FIG. 4;
FIG. 6 is a schematic of an embodiment of pre-orifices (e.g., a
first pre-orifice and a second pre-orifice) of the two fuel supply
systems of FIG. 5;
FIG. 7 is a schematic of an embodiment of a first fuel supply
system and a second fuel supply system coupled to a first combustor
of FIG. 4 and a third fuel supply system and a fourth fuel supply
system coupled to a second combustor of FIG. 4; and
FIG. 8 is a schematic of an embodiment of exemplary pre-orifices,
as may be associated with the first fuel supply system and the
third fuel supply system of FIG. 7.
DETAILED DESCRIPTION
One or more specific embodiments of the present invention will be
described below. In an effort to provide a concise description of
these embodiments, all features of an actual implementation may not
be described in the specification. It should be appreciated that in
the development of any such actual implementation, as in any
engineering or design project, numerous implementation-specific
decisions must be made to achieve the developers' specific goals,
such as compliance with system-related and business-related
constraints, which may vary from one implementation to another.
Moreover, it should be appreciated that such a development effort
might be complex and time consuming, but would nevertheless be a
routine undertaking of design, fabrication, and manufacture for
those of ordinary skill having the benefit of this disclosure.
When introducing elements of various embodiments of the present
invention, the articles "a," "an," "the," and "said" are intended
to mean that there are one or more of the elements. The terms
"comprising," "including," and "having" are intended to be
inclusive and mean that there may be additional elements other than
the listed elements.
The present disclosure is directed towards reducing combustion
dynamics and/or modal coupling of combustion dynamics, to reduce
unwanted vibratory responses in downstream components of a gas
turbine system and/or the combustors themselves. A gas turbine
combustor (or combustor assembly) may generate combustion dynamics
due to the combustion process, characteristics of intake fluid
flows (e.g., fuel, oxidant, diluent, etc.) into the combustor, and
various other factors. The combustion dynamics may be characterized
as pressure fluctuations, pulsations, oscillations, and/or waves at
certain frequencies. The fluid flow characteristics may include
velocity, pressure, fluctuations in velocity and/or pressure,
variations in flow paths (e.g., turns, shapes, interruptions,
etc.), or any combination thereof. Collectively, the combustion
dynamics can potentially cause vibratory responses and/or resonant
behavior in various components upstream and/or downstream from the
combustor, as well as the combustors themselves. For example, the
combustion dynamics (e.g., at certain frequencies, ranges of
frequencies, amplitudes, combustor-to-combustor phases, etc.) can
travel both upstream and downstream in the gas turbine system. If
the gas turbine combustors, upstream components, and/or downstream
components have natural or resonant frequencies that are driven by
these pressure fluctuations (i.e. combustion dynamics), then the
pressure fluctuations can potentially cause vibration, stress,
fatigue, etc. The components may include combustor liners,
combustor flow sleeves, combustor caps, fuel nozzles, turbine
nozzles, turbine blades, turbine shrouds, turbine wheels, bearings,
fuel supply assemblies, or any combination thereof. The downstream
components are of specific interest, as they are more sensitive to
combustion tones that are in-phase and coherent. Thus, reducing
coherence, altering phase and/or reducing the amplitudes of the
combustion dynamics specifically reduces the possibility of
unwanted vibrations in downstream components. One way to reduce the
coherence of the combustion dynamics among the combustors is to
alter the frequency relationship between two or more combustors,
diminishing any combustor-to-combustor coupling. As the combustion
dynamics frequency in one combustor is driven away from that of the
other combustors, modal coupling of combustion dynamics is reduced,
which, in turn, reduces the ability of the combustor tone to cause
a vibratory response in downstream components. An alternate method
of reducing modal coupling is to reduce the constructive
interference of the fuel nozzles within the same combustor, by
introduction of a phase delay between the fuel nozzles, reducing
the amplitudes in each combustor, and potentially preventing or
reducing combustor-to-combustor coupling. Furthermore, introducing
a phase lag between the combustors, or otherwise altering the phase
relationship between two or more combustors may also help to
prevent or reduce unwanted vibrations in the gas turbine
system.
As discussed in detail below, the disclosed embodiments may vary
the physical characteristics of a pre-orifice within a fuel line of
a fuel supply assembly (e.g., late lean injection (LLI) fuel
circuit) to modify the fuel system acoustic impedance, which may
lead to combustion dynamics frequencies in one or more combustors
that are different, phase shifted, smeared or spread out over a
greater frequency range, or any combination thereof, relative to
any resonant frequencies of the components in the gas turbine
system. As noted above, a gas turbine system may include one or
more combustor assemblies (e.g., combustor cans, combustors, etc.),
and each combustor may be configured with a primary combustion zone
and a secondary combustion zone. Specifically, in some embodiments,
the secondary combustion zone may include an LLI fuel circuit
configured to route a secondary fuel into a secondary combustion
zone for combustion. In certain embodiments, each LLI fuel circuit
includes one or more fuel lines extending along either the liner or
the flow sleeve of the combustor, and each fuel line is configured
to provide a secondary fuel to one or more fuel injectors that
route the secondary fuel into the secondary combustion zone. In
particular, each of the one or more LLI fuel lines may include one
or more pre-orifices through which the fuel flows in the LLI fuel
circuit prior to arriving at the LLI fuel nozzles, where the fuel
is injected into the combustor through one or more post-orifices.
The fuel system acoustic impedance of the fuel nozzles is defined
by the geometry of the pre-orifice, the geometry of the
post-orifice and the volume between the pre and post-orifice.
Accordingly, varying the position of the pre-orifice within the LLI
fuel circuit adjusts the volume between the pre and post orifice,
to adjust the fuel system acoustic impedance of one or more fuel
nozzles. In addition, altering the size, shape and/or number of
holes in the pre-orifice may also alter the fuel system acoustic
impedance of one or more fuel nozzles.
In certain embodiments, the physical characteristics (e.g.,
position, sizing, shape, location, effective area, etc.) of the
pre-orifice of each fuel line within the LLI fuel circuit of a
single combustor may be different from the physical characteristics
of the pre-orifice of another fuel line within the same LLI fuel
circuit. For example, the location of the pre-orifice along the LLI
fuel line may be shifted, so that it is closer or further away from
the post-orifice, thus changing the acoustic volume between the pre
and post orifices, thereby altering the fuel system impedance. By
further example, the location of the pre-orifice relative to the
post-orifice may be shifted relative to other fuel lines of the
same combustor, thus changing the acoustic volume between the pre
and post orifices and thereby altering the fuel system impedance.
Further, in certain embodiments, the physical characteristics of
the pre-orifices of the one or more fuel lines within a single
combustor may be different from the physical characteristics of the
pre-orifices of one or more fuel lines within another (e.g.,
adjacent, alternating) combustor within the gas turbine system. For
example, the location of the pre-orifice relative to the
post-orifice along the LLI fuel lines of a first combustor may be
shifted when compared to the location of the pre-orifice relative
to the post-orifice of another combustor (e.g., an adjacent
combustor), thereby changing the acoustic volume between the pre
and post orifices and thus altering the fuel system impedance
between different combustors within the gas turbine system.
In some embodiments, by varying the physical characteristics of the
pre-orifice (e.g., location, size, position, shape, effective area,
etc.) of one or more fuel lines within the LLI fuel circuit of the
combustor, the magnitude and phase of the fuel system impedance for
the fuel nozzle will be changed, which affects the fluctuating
component of the heat release, and therefore the combustion
dynamics of the combustor. Varying the fuel system impedance
between two or more fuel lines within a combustor by varying the
physical characteristics of two or more pre-orifices results in
different fuel system acoustic impedance magnitudes and phases for
the different fuel nozzles. The difference in the phase of the fuel
system impedance between the fuel nozzles results in destructive
interference of the heat release fluctuations associated with each
of the fuel nozzles, reducing the amplitude of the combustion
dynamics, and potentially smearing the frequency content of the
combustion dynamics across a broader frequency range.
In some embodiments, the physical characteristics of the
pre-orifice (e.g., location, size, position, shape, effective area,
etc.) of each fuel line within a particular combustor may be the
same, but may be varied compared to the pre-orifices of fuel lines
within other combustors within the system. Varying the physical
characteristics of the pre-orifices among the fuel lines of various
combustors may vary the fuel system acoustic impedance and
therefore, combustion dynamics, from combustor to combustor in a
manner to reduce the combustion dynamics amplitudes, alter the
combustion dynamics frequency, alter the phase of the combustion
dynamics, and/or reduce modal coupling of the combustion dynamics
among the plurality of gas turbine combustors. In some embodiments,
the physical characteristics of the pre-orifice may be varied
within a particular combustor, as well as among one or more
combustors of the system in order to reduce dynamic amplitudes as
well as coherence within and/or among the combustors of the system.
For example, the physical characteristics of the pre-orifices among
the combustors may be varied according to various patterns or
groupings, as further explained below. Indeed, such variations may
help reduce the amplitudes of the combustion dynamics and/or reduce
the possibility of modal coupling of the combustors, particularly
at frequencies that are aligned with resonant frequencies of the
components of the gas turbine system.
With the forgoing in mind, FIG. 1 is a schematic of an embodiment
of a gas turbine system 10 having a plurality of combustors 12 and
a fuel supply circuit 14, such as an LLI fuel circuit 14. In
particular, each combustor 12 may be associated with a fuel circuit
14 that routes a liquid and/or gas fuel into the combustors 12. For
example, the fuel circuit 14 may be configured to route a liquid
and/or gas secondary fuel 16 (e.g., secondary fuel 16, second fuel
16) to one or more fuel supply systems 18 of the combustor 12. Each
fuel supply system 18 of the combustor 12 includes a pre-orifice 20
disposed along a fuel conduit 22 (as illustrated in FIG. 2) of the
combustor 12, and a post-orifice 24 disposed along the fuel conduit
22, and generally disposed within a fuel nozzle, such as a
secondary fuel nozzle (as illustrated in FIG. 2) of the combustor
12. The secondary fuel 16 may be provided to the combustor 12 from
the fuel circuit 14. From the fuel circuit 14, the fuel flows
through the pre-orifice 20 in the fuel conduit 22, and may be then
routed through the secondary fuel nozzle 64 via one or more
post-orifices 24. As noted above, varying the geometries of the
pre-orifices 20 as described above may adjust the fuel system
acoustic impedance of one or more of the secondary nozzles 64,
thereby leading to a shift in combustion dynamics frequency and/or
greater variations in the frequency content of the resulting
combustion dynamics, and/or reduced amplitudes of the combustion
dynamics.
The gas turbine system 10 includes the one or more combustors 12
having the fuel line systems 18, a compressor 26, and a turbine 28.
The combustors 12 include primary fuel nozzles 30 which route a
primary fuel 32 (e.g., liquid fuel and/or a gas fuel, a first fuel,
etc.) into the combustors 12 for combustion within the primary
combustion zone. Likewise, the combustors 12 include secondary fuel
nozzles 64 (as illustrated in FIG. 2) which route a secondary fuel
16 into the combustors 12 for combustion within the secondary
combustion zone. In particular, each combustor 12 is associated
with the LLI fuel circuit 14 configured to provide the secondary
fuel 16 to the one or more secondary fuel nozzles 64 via the one or
more fuel conduits 22. The combustors 12 ignite and combust an
air-fuel mixture, and then the hot combustion gases 34 are passed
into the turbine 28. The turbine 28 includes turbine blades that
are coupled to a shaft 36, which is also coupled to several other
components throughout the system 10. As the combustion gases 34
pass through the turbine blades in the turbine 28, the turbine 28
is driven into rotation, which causes the shaft 36 to rotate.
Eventually, the combustion gases 34 exit the turbine system 10 via
an exhaust outlet 38. Further, the shaft 36 may be coupled to a
load 40, which is powered via rotation of the shaft 36. For
example, the load 40 may be any suitable device that may generate
power via the rotational output of the turbine system 10, such as a
power generation plant or an external mechanical load. For
instance, the load 40 may include an electrical generator, a
propeller of an airplane, and so forth.
In an embodiment of the turbine system 10, compressor blades are
included as components of the compressor 26. The blades within the
compressor 26 are coupled to the shaft 36, and will rotate as the
shaft 36 is driven to rotate by the turbine 28, as described above.
The rotation of the blades within the compressor 26 compresses air
43 from an air intake 42 into pressurized air 44. The pressurized
air 44 is then fed into the primary fuel nozzles 30 of the
combustors 12. The primary fuel nozzles 30 mix the pressurized air
44 and fuel to produce a suitable mixture ratio for combustion
(e.g., a combustion that causes the fuel to more completely burn)
so as not to waste fuel or cause excess emissions.
As discussed in further detail below, the physical characteristics
(e.g., position, size, location, shape, effective area, etc.) of
the pre-orifice 20 may vary between different fuel conduits 22 of
the same combustor 12 (as shown in FIGS. 5 and 6), and/or may vary
between different fuel conduits 22 of different combustors 12
within the same gas turbine system 10 (as shown in FIGS. 7 and 8).
As noted above, changing the physical characteristics of the
pre-orifice 20 and/or the volume between the pre-orifice and the
post-orifice 24 between different fuel conduits 22 of the same
combustor 12 may help vary the fuel system acoustic impedance, and
thereby help reduce unwanted vibratory responses within the
combustor and/or in downstream components of the system 10.
Likewise, changing the physical characteristics of the pre-orifice
20 and/or the volume between the pre-orifice and the post-orifice
24 between fuel conduits 22 of different combustors 12 may help
vary fuel system acoustic impedances, thereby helping to reduce
amplitudes and/or coherence of the combustion dynamics, and/or
alter the phase of the combustion dynamics.
In some embodiments, changes in the physical characteristics of the
pre-orifice 20 for a specific fuel nozzle may change the effective
area and/or the pressure ratio for that fuel nozzle, which in turn
may result in variations of the mass flow of the secondary fuel 16
entering the combustor 12. For example, the shape of the
pre-orifice 20 (e.g., round, oval, square, polygonal, etc.) may be
varied between and/or among different combustors 12 to vary the
effective area and/or the pressure ratio of the pre-orifice 20
which would vary the mass flow of secondary fuel 16 entering the
combustor 12. As a further example, shifting the location of the
pre-orifice 20 relative to the post-orifice 24 (e.g., closer to the
post-orifice 24 or away from the post-orifice 24) may increase or
decrease the acoustic volume between the pre-orifice 20 and the
post-orifice 24, thereby resulting in a phase delay between one or
more secondary fuel nozzles 64, and causing destructive
interference of the equivalence ratio fluctuations generated by the
fuel nozzles 64. In this manner, changing the physical
characteristics may result in variations between the heat release
of the LLI injectors within the combustor, thereby increasing the
amount of temporal variation in the dynamic frequency content in
the flame region, and/or increasing the destructive interference of
the dynamic frequency content in the flame region, which may result
in reducing the amplitude of the combustor tones and/or the
coherence of the combustion dynamics.
In some embodiments, the size and/or shape of the pre-orifice 20
may vary between different fuel conduits 22 of the same combustor
12 (as shown in FIGS. 5 and 6), and/or may vary between different
fuel conduits 22 of different combustors 12 within the same gas
turbine system 10 (as shown in FIGS. 7 and 8). Further, while
variations on the pre-orifice 20 are described, it should be noted
that changes in the physical characteristics of the post-orifice 24
(e.g., size, shape, location, position, effective area, etc.) may
also help reduce the amplitudes of the combustion dynamics within
the system 10. Likewise, varying the physical characteristics of
the fuel conduit 22 (e.g., length, width, circumference, diameter,
effective area, etc.) in order to change the distance and the
acoustic volume between the pre-orifice 20 and the post-orifice 24
may help reduce unwanted vibratory responses within the gas turbine
system 10.
FIG. 2 is a schematic view of an embodiment of one of the
combustors 12 depicted in FIG. 1, where the combustor 12 includes
the fuel supply system 18 (e.g., a first fuel supply system 17, a
second fuel supply system 19, etc.) having the pre-orifice 20 and
the post-orifice 24 disposed along the fuel conduit 22. It should
be noted in certain embodiments; the pre-orifice 20 may be disposed
anywhere along the fuel conduit 22, as illustrated in FIG. 2. In
particular, the physical characteristics (e.g., location, size,
shape, dimensions, position) of the components of the fuel supply
system 18 (e.g., the pre-orifice 20, the fuel conduit 22, and the
post-orifice 24) may be varied between different fuel supply
systems 18 of the combustor 12. For example, the position of the
pre-orifice 20 relative to the post-orifice 24 (and thus
intermediate distance and volume) of the first fuel supply system
17 may be different than the position of the pre-orifice 20 (and
thus intermediate distance and volume) relative to the post-orifice
24 of the second fuel supply system 19, as described in detail
below. Such variations may vary the fuel system acoustic impedance
of the associated secondary fuel nozzles 64 leading to combustion
dynamics frequencies that are different and/or phase-shifted
between the fuel nozzles 64 and/or between combustors 12, thereby
reducing unwanted vibratory responses in the gas turbine system 10.
For example, maximum destructive interference between the fuel
nozzles 64 occurs when the phase delay between the fuel nozzles 64
is approximately 180 degrees.
The combustor 12 includes a head end 50 having an end cover 52, a
combustor cap assembly 54, and a primary combustion zone 56. The
end cover 52 and the combustor cap assembly 54 may be configured to
support the primary fuel nozzles 30 in the head end 50. In the
illustrated embodiment, the primary fuel nozzles 30 route the
primary fuel 32 to the primary combustion zone 56. The combustor 12
includes an outer wall (e.g., flow sleeve 68) disposed
circumferentially about an inner wall (e.g., combustion liner 66).
The inner wall may also include a transition piece 69, which
generally converges towards a first stage of the turbine 28. An
impingement sleeve 67 is disposed circumferentially about the
transition piece 69. Further, the primary fuel nozzles 30 receive
the pressurized air 44 from the annulus 58 (e.g., between
transition piece 69 and impingement sleeve 67 and between liner 66
and flow sleeve 68) of the combustor 12 and combine the pressurized
air 44 with the primary fuel 32 to form an air/fuel mixture that is
ignited and combusted in the primary combustion zone 56 to form
combustion gases (e.g., exhaust).
The combustion gases flow in a direction 60 to a secondary
combustion zone 62. The LLI fuel circuit 14 provides the secondary
fuel 16 which flows through the pre-orifice 20 in the fuel conduit
22 to the post-orifice 24. In particular, the post-orifice 24 in
the secondary fuel nozzles 64 receive the secondary fuel 16 from
the fuel conduit 22, and route the secondary fuel 16 into the
secondary combustion zone 62 to the stream of combustion gases.
Further, the secondary fuel nozzles 64 may receive the pressurized
air 44 from the annulus 58 of the combustor 12 and combine the
pressurized air 44 with the secondary fuel 16 to form an air/fuel
mixture that is ignited and combusted in the secondary combustion
zone 62 to form the combustion gases. More specifically, the
pressurized air 44 flows through the annulus 58 between a
transition piece 69 and an impingement sleeve 67, and then between
a liner 66 and a flow sleeve 68 of the combustor 12 to reach the
head end 50. The combustion gases flow in the direction 60 through
the transition piece 69 of the combustor 12, and pass into the
turbine 28, as noted above.
As described above, combustion dynamics (e.g., generation of hot
combustion gases) within the primary combustion zone 56 and the
secondary combustion zone 62 may lead to unwanted vibratory
responses within the combustor 12. In may be helpful to reduce
combustion dynamics within or among the combustors 12 to help
reduce unwanted vibratory responses. Accordingly, in some
embodiments, varying the physical characteristics of the
pre-orifice within and/or among the combustors 12 may help reduce
vibratory responses in the gas turbine system 10, and minimize
vibrational stress, wearing, performance degradation, or other
undesirable impacts to the components of the gas turbine system 10
(e.g., turbine blades, turbine shrouds, turbine nozzles, exhaust
components, combustor transition piece, combustor liner, etc.).
In some embodiments, the position of the pre-orifice 20 relative to
the post-orifice 24 (and thus the intermediate distance and volume)
may be varied between the fuel supply systems 18 of the combustor
12, such that the pre-orifice 20 is shifted along the fuel conduit
22 to be closer to or further away from the post-orifice 24 and the
secondary fuel nozzles 64. For example, a first distance 72 between
the pre-orifice 20 and the post-orifice 24 of the first fuel supply
system 17 may be different (e.g., longer, shorter, greater,
smaller, etc.) than a second distance 74 between the pre-orifice 20
and the post-orifice 24 of the second fuel supply system 19.
Indeed, the distances may vary or may be configured to vary based
on the location where the pre-orifice 20 is disposed along the fuel
conduit 22. In certain embodiments, varying the distance 72, 74
between the pre-orifice 20 and the post-orifice 24 may be done by
increasing or decreasing the length of the fuel conduit 22 upstream
and downstream of the pre-orifice via one or more sections of
flanged tubing. In certain embodiments, the length of the fuel
conduits 22 may be the same between the fuel supply systems 18, but
the location of the pre-orifices 20 disposed along the fuel conduit
22 may vary between the fuel supply systems 28. Indeed, varying the
distance (e.g., the first distance 72 and the second distance 74 of
the pre-orifice 20 relative to the post-orifice 24) between the
fuel supply systems 18 may result in phase delays between the fuel
supply systems 18, leading to destructive interference of the heat
release fluctuations of the fuel nozzles 64 associated with each
fuel supply system 18, thereby reducing the amplitude of the
combustor tones and possibly the coherence of the combustion
dynamics.
Further, in some embodiments, physical characteristics (e.g.,
position, location, size, shape, dimensions, effective area, etc.)
of other components of the fuel supply system 18 may vary between
different fuel supply systems 18 (e.g., the first fuel supply
system 17 and the second fuel supply system 19), as further
described with respect to FIG. 3. For example, the size and/or
effective area of the pre-orifice 20 or the post-orifice 24 (e.g.,
diameter of the opening of the pre-orifice 20 or the post-orifice
24), the shape of the pre-orifice 20 or the post-orifice 24 opening
(e.g., oval, circular, rectangular, any geometric shape, etc.), the
angle of pre-orifice 20 or the post-orifice 24 opening (e.g.,
slanted upward at an angle, slanted downward at an angle, etc.),
and so forth may vary between the fuel supply systems 18. Further,
in some embodiments, the pre-orifice 20 and the post-orifice 24 may
be an array or pattern of holes. In such embodiments, the size, the
shape, the pattern and/or arrangement of the pre-orifice 20 holes
and the post-orifice 24 holes may vary between different fuel
conduits 22 of the combustor 12. In some embodiments, the
pre-orifice 20 and/or the post-orifice 24 may vary among the
plurality of combustors 12 (e.g., 2, 3, 4, 5, 6, 7, 8, 9, 10, or
more combustors 12) with different diameters, shapes, sizes,
etc.
In addition, the physical characteristics of the fuel conduit 22
may also vary between different fuel conduits 22 of the combustor
12. For example, in addition to varying the length (e.g., the first
distance 72 or the second distance 74) of the fuel conduits 22, the
disclosed embodiments may also vary the diameter of the fuel
conduit 22, and so forth. Indeed, one or more physical
characteristics of the disclosed embodiments also may vary each
component within the fuel supply system 18 between different fuel
supply systems 18 of the combustor 12, such that the combustion
dynamics at each secondary fuel nozzle 64 are different (in terms
of phase and/or frequency) to help reduce unwanted vibratory
responses within the gas turbine system 10.
In some embodiments, the dynamic amplitudes as well as coherence
may be reduced between different combustors 12 of the system 10 by
varying the physical characteristics of the pre-orifices among the
combustors 12, as further described with respect to FIG. 4. For
example, while the position of the pre-orifice 22 relative to the
post-orifice 24 may be the same among the fuel supply systems 18 of
a single combustor 12, the position of the pre-orifice 22 relative
to the post-orifice 24 may be varied between fuel supply systems 18
of different combustors 12 within the system 10. Further, the
physical characteristics (e.g., size, position, shape, location,
dimensions, effective area, etc.) of the components of the fuel
supply system 18 (e.g., the pre-orifice 20, the fuel conduit 22,
the post-orifice 24) may vary between different combustors 12 of
the system 10. In some embodiments, the physical characteristics of
the components of the fuel supply system 28 may vary between fuel
lines 18 of the same combustor 12, as well as between fuel lines 18
of different combustors 12.
FIG. 3 is a cross-sectional view of an embodiment of the combustor
12 depicted in FIG. 2, illustrating one or more fuel supply systems
18 each receiving the secondary fuel 16. Particularly, the
secondary fuel 16 is routed through the pre-orifice 20, through the
fuel conduit 22, and then through the post-orifice 24, of the
secondary fuel nozzles 64 (as illustrated in FIG. 2). The fuel
conduits 22, composed of one or more sections of flanged tubing,
extend along the outside of the flow sleeve 68 of the combustor 12,
as illustrated in FIG. 2, such that the fuel conduits 22 route the
secondary fuel 16 from the pre-orifice 20 to the one or more
secondary fuel nozzles 64. While the illustrated embodiment depicts
the fuel conduits 22 with alternating large and small diameters, as
further explained below, it should be noted that in other
embodiments, the fuel conduits 22 may have any sized diameters.
In particular, the physical characteristics of the components of
each fuel supply system 18 within the combustor 12 may vary, such
that the size, shape, dimensions, configuration, position,
location, and so forth, are different between the fuel supply
systems 18 of a single combustor 12 and/or between adjacent
combustors 12. For example, in the illustrated embodiment, the size
of the pre-orifice 20 and the fuel conduit 22 is different for each
adjacent fuel supply system 18. For example, a first diameter 78 of
the fuel conduit 22 of the first fuel supply system 17 is greater
than a second diameter 80 of the fuel conduit 22 of the second fuel
supply system 19. It should be noted that while the illustrated
embodiment depicts alternating and/or adjacent fuel supply systems
18 (e.g., the first supply system 17 and the second fuel supply
system 19) having variations in the physical characteristics of the
pre-orifice 20 and/or the fuel conduit 22, in other embodiments,
any combination and/or pattern of fuel supply systems 18 may have
variations in the physical characteristics of the components of the
fuel supply systems 18. Further, there may be one or more physical
characteristics variations between any two fuel supply systems 18.
As noted above, the illustrated embodiment depicts fuel conduits 22
that alternate between the first diameter 78 and the second
diameter 80. In other embodiments, the diameter size of the fuel
conduits 22 may alternate between 2, 3, 4, 5, 6, 7, 8, 9, 10 or
more different sizes, shapes, etc.
FIG. 4 is a schematic of an embodiment of the gas turbine system 10
of FIG. 1, depicting a plurality of combustors 12 each having one
or more fuel supply systems 18. In particular, each fuel supply
system 18 includes various components such as the pre-orifice 20,
the fuel conduit 22, and the post-orifice 24, and the physical
characteristics (e.g., size, position, dimensions, location, shape,
geometric characteristics, etc.) of one or more components of the
fuel supply system 18 may vary within and/or between the one or
more combustors 12 of the system 10. As noted above, variations
within the components of the fuel supply systems 18 of a single
combustor 12 and/or between the components of fuel supply systems
18 of one or more combustors 12 result in changes to the fuel
system acoustic impedance for one or more fuel nozzles 64, thereby
leading to a shift in combustion dynamics frequency and/or greater
variations in the frequency content of the resulting combustion
dynamics, and/or reduced amplitudes of the combustion dynamics,
and/or differences in phase of the combustion dynamics between two
or more combustors 12. In particular, the illustrated embodiment
depicts the variations of the fuel supply systems 18 within the
combustor 12 and/or between combustors 12.
In the illustrated embodiment, the gas turbine system 10 includes
four combustors 12 coupled to the turbine 28. However, in other
embodiments, the gas turbine system 10 includes any number of
combustors 12 (e.g., 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
15, 16, or more combustors). In particular, each combustor 12
includes the fuel circuit 14 configured to provide the secondary
fuel 16 to the pre-orifice 20 positioned in the fuel conduit 22
near the head 50 of the combustor 12. Further, the secondary fuel
16 is routed through the pre-orifice 20, through the fuel conduit
22, and through the post-orifice 24. In particular, the
post-orifice 24 is configured to route the secondary fuel 16 from
the secondary fuel nozzle 64, into the secondary combustion zone
62. As noted above, combustors 12 ignite and combust the air-fuel
mixture (e.g., the secondary fuel 16 and/or compressed air 44), and
then the hot combustion gases 34 are passed into the turbine 28. As
the combustion gases 34 pass through the turbine blades in the
turbine 28, various combustion dynamics may produce unwanted
vibratory responses.
In some embodiments, the components of the fuel supply system 18
within the combustor 12 have variability among other components of
the fuel supply system 18 within the same combustor 12. For
example, in a first combustor 75, the first distance 72 (and
thereby the acoustic volume) between the pre-orifice 20 and the
post-orifice 24 of the first fuel supply system 17 is greater than
a second distance 74 (and thereby the acoustic volume) between the
pre-orifice 20 and the post-orifice 24 of the second fuel supply
system 19. Particularly, in the illustrated example, the
pre-orifice 20 is shifted along the fuel conduit 22 so that it is
closer or further away from the post-orifice 24. As noted above,
varying the distance between the pre-orifice 20 and the
post-orifice 24 varies the acoustic volume between the pre-orifice
20 and the post orifice 24, and may be done by increasing or
decreasing the length (and/or diameter) of one or more sections of
tubing (e.g. flanged tubing), making up the fuel conduit 22. The
pre-orifice 20 can be contained between the flanges (e.g. sandwich
plate), or embedded as part of one of the sections of tubing. By
varying the length of the sections of fuel conduit 22 positioned
upstream and downstream of the pre-orifice 20, the distance (and/or
diameter) between the pre-orifice and the post-orifice can be
varied between fuel supply systems 18. Further, varying the
acoustic volume among different fuel supply systems 18 (e.g., first
fuel supply system 17 and the second fuel supply system 19) within
the same combustor (e.g., the first combustor 75) may help to vary
the fuel system impedance between the combustors 12. It should be
noted that in other embodiments, as shown in FIG. 7, the combustor
12 may have variability among other fuel supply system 18
components, such as the size and/or shape and/or effective areas of
the pre-orifice 20 or the post-orifice 24, the length of the fuel
conduit 22, the diameter of the fuel conduit 22, the volume of the
fuel conduit 22, the construction material of the components of the
fuel supply systems 18, and so forth.
In some embodiments, the components of the fuel supply system 18
within the combustor 12 may have variability compared to the
components of the fuel supply systems 18 among other combustors 12
within the system 10 (as shown in FIGS. 4, 7, and 8. For example,
while the physical characteristics of the components (e.g., the
pre-orifice 20, the fuel conduit 22, the post-orifice 24) of the
fuel supply systems 18 of the second combustor 77 may be
substantially similar, in some embodiments, the physical
characteristics of the components of the fuel supply systems 18 of
the second combustor 77 may be different from the physical
characteristics of the fuel supply systems 18 of the first
combustor 75 (e.g., the first fuel supply system 17 and/or the
second fuel supply system 19), and the physical characteristics of
the components of the fuel supply system 18 of the third combustor
79 may be different from the physical characteristics of the fuel
supply systems 18 of the first combustor 75 and/or the second
combustor 77 as in FIGS. 7 and 8). In the illustrated embodiment,
the distance of the pre-orifice 20 relative to the post-orifice 24
of the second combustor 77 may be different between one or more
fuel supply systems 18 of the second combustor 77. In other words,
the position of the pre-orifice 20 along the fuel conduit 22
relative to the post-orifice 24 may be different between the fuel
supply systems 18 of the second combustor 77. Indeed, it should be
noted that the pre-orifice 20 may be disposed anywhere along the
fuel conduit 22, such that the distance between the pre-orifice 20
and the post-orifice 24 along the fuel conduit 22 may be different
between fuel supply systems 18 despite having a substantially
similar length fuel conduit 22, as illustrated in the second
combustor 77. Further, the position of the pre-orifice 20 along the
fuel conduit 22 relative to the post-orifice 24 (e.g., the distance
between the pre-orifice 20 and the post-orifice 24) within the
second combustor 77 is different than the first distance 72 and/or
the second distance 74 within the first combustor 75. Accordingly,
the combustion dynamics and the acoustic fuel system impedance of
the first combustor 75 relative to the second combustor 77 are
different, thereby helping to reduce combustion dynamic amplitudes
and/or possibly modal coupling of the combustion dynamics between
the two combustors 12, and/or alter the phase delay between the two
combustors 12.
In some embodiments, as shown in FIGS. 5 and 7, other physical
characteristics may be varied between the components of the fuel
supply systems 18 within the same combustor 12. For example, in the
illustrated embodiment, the first diameter 78 of a third fuel
supply system 21 of a third combustor 79 is larger than the second
diameter 80 of a fourth fuel supply system 23 of the same third
combustor 79. In some embodiments, the first distance 72 of the
third fuel supply system 21 is greater than the second distance 74
of the fourth fuel supply system 23. Further, in some embodiments,
the shape or physical configuration of the fuel supply systems 18
may vary within and/or between the combustors 12. For example, in a
fourth combustor 81 shown in FIG. 4, the shape of the fuel conduit
22 within the fuel supply system 25 is curved convexly towards the
exit 70 of the fourth combustor 81. In other physical
configurations of the fuel supply system 18, the shape of the fuel
conduit 22 may include one or more angles (e.g., jagged shape),
waves, rough edges, and so forth, such that the one or more tubing
sections of the fuel conduit 22 is shaped differently than adjacent
fuel conduits 22 within or between the combustors 12. For example,
a fuel supply system 27 of the fourth combustor 81 includes a fuel
conduit 22 in a wave form. Further, in some embodiments, the fuel
conduits 22 may include protrusions 82 (e.g., waves, rough edges,
angles, and so forth) on an inner surface 84 of the fuel conduit 22
that provides variations in the fuel flow of the secondary fuel 16.
The protrusions 82 may be formed from the same material as the fuel
conduit 22. As noted above, such variations of the physical
characteristics between various components of the fuel supply
systems 18 help to reduce the amplitudes of the combustor tones
and/or the coherence of the combustion dynamics.
FIG. 5 is a schematic of an embodiment of the third fuel supply
system 21 and the fourth fuel supply system 23 of the third
combustor 79, where the third combustor 79 is illustrated in FIG.
4. Specifically, the illustrated embodiment depicts physical
variations between the third fuel supply system 21 and the fourth
fuel supply system 23, such as variations in distance between the
pre-orifice 20 and the post-orifice 24 and variations in diameter
of the fuel conduit 22. For example, the first distance 72 between
the pre-orifice 20 and the post-orifice 24 of the third fuel supply
system 21 is greater than the second distance 74 between the
pre-orifice 20 and the post-orifice 24 of the fourth fuel supply
system 23. Further, the first diameter 78 of the fuel conduit 22 of
the third fuel supply system 21 is greater than the second diameter
80 of the fuel conduit 22 of the fourth fuel supply system 23.
Accordingly, a first acoustic volume 83 within the third fuel
supply system 21 may be greater than a second acoustic volume 85
within the fourth fuel supply system 23. It should be noted that in
other embodiments, the first acoustic volume 83 within a particular
fuel supply system 18 may be different than the second acoustic
volume 85 within another (e.g., adjacent) fuel supply system
18.
In some embodiments, other variations between the fuel supply
systems 18 (e.g., the third fuel supply system 21 and the fourth
fuel supply system 23) may exist. In certain embodiments, the width
of the pre-orifice 20 may vary between different fuel supply
systems 18. For example, a first width 86 (or diameter,
cross-sectional area, shape, etc.) of the pre-orifice 20 in the
third fuel supply system 21 may be greater than a second width 88
(or diameter, cross-sectional area, shape, etc.) of the pre-orifice
20 in the fourth fuel supply system 23. Similarly, a third width 90
(or diameter, cross-sectional area, shape, etc.) of the
post-orifice 24 of the third fuel supply system 21 may be greater
than a fourth width 92 (or diameter, cross-sectional area, shape,
etc.) of the post-orifice 24 of the fourth fuel supply system 23.
Further, the width of the pre-orifice 20 (e.g., the first width 86
and/or the second width 88) may be different than the width of the
post-orifice 24 (e.g., the third width 90 and/or the fourth width
92) within and/or between the fuel supply systems 18 (e.g., between
the fuel supply systems 21 and 23).
In yet other embodiments, the pre-orifices 20 and/or the
post-orifices 24 may have physical characteristics (e.g., shape,
dimensions, holes, thickness, material, arrangement, pattern, hole
shape, hole size, etc.) that are different within and/or between
combustors 12. For example, a first pre-orifice 94 of the third
fuel supply system 21 may be different than a second pre-orifice 96
of the fourth fuel supply system 23, as explained further with
respect to FIG. 6.
FIG. 6 is a schematic of an embodiment of the pre-orifices 20 of
the fuel supply systems 18. Specifically, the pre-orifice 94 of the
third fuel supply system 21 may have physical characteristics that
vary from the second pre-orifice 96 of the fourth fuel supply
system 23. For example, the pre-orifices 94 and 96 have differences
in hole shapes and patterns, which may change the effective area
and/or the pressure ratio of the mass flow of the secondary fuel 16
through the pre-orifices 94 and 96. In the illustrated embodiment,
the pre-orifice 94 may include five circular holes arranged in an
annular pattern around a central hole 100. Further, the pre-orifice
96 may include five triangular holes 102 arranged in an annular
pattern around a central square 104. However, it should be noted
that in other patterns and configurations, any number of holes
(e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, etc.) may be arranged in any
shape or pattern (symmetrical, spirals, random, waves, checkered,
etc.), such that the pre-orifices 94 and 96 are different from one
another.
In some embodiments, as shown in FIG. 7, variations between the
fuel supply systems 18 in different combustors (e.g., between the
first fuel supply system 17 of the first combustor 75 and the third
fuel supply system 21 of the second combustor 79) may exist,
instead of, or in addition to, differences between the fuel supply
systems 18 of each combustor. In the first fuel supply system 17 of
the first combustor 75, the pre-orifice 20 has a first thickness
106 and multiple orifice holes, each having a width 116 (or
diameter, cross-sectional area, shape, etc.); the fuel conduit 22
has a first diameter 126; the post-orifice 24 defines a first width
136; and a first acoustic volume 123 is defined over the distance
72 between the pre-orifice 20 and the post-orifice 24. In the
second fuel supply system 19 of the first combustor 75, the
pre-orifice 20 has a second thickness 108 and an orifice hole
having a width 118 (or diameter, cross-sectional area, shape,
etc.); the fuel conduit 22 has a second diameter 128; the
post-orifice 24 defines a second width 138; and a second acoustic
volume 133 is defined over the distance 74 between the pre-orifice
20 and the post-orifice 24. In the third fuel supply system 21 of
the third combustor 79, the pre-orifice 20 has a third thickness
112 and an orifice hole having a width 86 (or diameter,
cross-sectional area, shape, etc.); the fuel conduit 22 has a third
diameter 78; the post-orifice 24 defines a third width 90; and a
third acoustic volume 83 is defined over the distance 72 between
the pre-orifice 20 and the post-orifice 24. In the fourth fuel
supply system 23 of the third combustor 79, the pre-orifice 20 has
a fourth thickness 114 and an orifice hole having a width 88 (or
diameter, cross-sectional area, shape, etc.); the fuel conduit 22
has a fourth diameter 80; the post-orifice 24 defines a fourth
width 92; and a fourth acoustic volume 85 is defined over the
distance 74 between the pre-orifice 20 and the post-orifice 24.
As illustrated, the first fuel supply system 17 of the first
combustor 75 has components that are different from the third fuel
supply system 21 of the third combustor 79 (e.g., in number of
orifices, width/size of pre-orifice, thickness of pre-orifice,
diameter of fuel conduit, and/or width of post-orifice), even
though the distance 72 between the pre-orifice 20 and the
post-orifice 24 is the same. Additionally, or alternately, the
second fuel supply system 19 of the first combustor 75 has
components that are different from the fourth fuel supply system 23
of the third combustor 79 (e.g., in number of orifices, width/size
of pre-orifice, thickness of pre-orifice, diameter of fuel conduit,
and/or width of post-orifice), even though the distance 74 between
the pre-orifice 20 and the post-orifice 24 is the same. The
differences in the number of orifices and the width/size of the
pre-orifices is shown schematically in FIG. 8.
Technical effects of the invention include reducing unwanted
vibratory responses associated with combustion dynamics within or
among combustors 12 of the gas turbine system 10 by varying the
physical characteristics of the pre-orifice 20 within the one or
more fuel supply systems 18 of the combustor 12 to adjust the fuel
system acoustic impedance (magnitude and phase) within the system
10. For example, from one fuel conduit 22 to another, the position
of the pre-orifice 20 may be shifted along the fuel conduit 22, so
that it is closer or further away from the post-orifice 24, thereby
changing the acoustic volume between the pre-orifice 20 and the
post-orifice 24. In other embodiments, the physical characteristics
of other components of the fuel supply systems 18 (e.g., the
post-orifice 24, the fuel conduit 22, and the pre-orifice 20) may
be varied within or among the combustors 12. For example, the
dimensions (e.g., length, width, diameter, volume) of the fuel
conduit 22, the size and/or shape (e.g., width, length, diameter,
effective area) of the pre-orifice 20 and/or the post-orifice 24,
the patterns or configurations of the pre-orifice 20 or the
post-orifice 24 (e.g., holes, arrangements of the holes, etc.), the
shape of the fuel conduit 22, the inner surface of the fuel conduit
22, and so forth, may vary between one or more fuel supply systems
18 within the same combustor 12 or among different combustors
12.
This written description uses examples to disclose the invention,
including the best mode, and also to enable any person skilled in
the art to practice the invention, including making and using any
devices or systems and performing any incorporated methods. The
patentable scope of the invention is defined by the claims, and may
include other examples that occur to those skilled in the art. Such
other examples are intended to be within the scope of the claims if
they have structural elements that do not differ from the literal
language of the claims, or if they include equivalent structural
elements with insubstantial differences from the literal language
of the claims.
* * * * *
References